With Ulisses, Julie and Jan from the IAS at Durham, I headed out on a bright but chilly February day to visit James Turrell’s Skyspace at Kielder Forest, situated a mile and a half from the nearest metalled road, amidst a coniferous plantation. It takes the form of a broad, low tower built from local stone, with a passageway leading into a circular chamber. A concrete bench surrounds its inner circumference, painted grey like the lower wall, which is detached like a thick skin and rises at an outward angle to about 8 feet. A higher wall, painted white, extends to the ceiling, at an angle leaning towards the perpendicular. It joins the ceiling which covers an area of some three feet, at which point a perfectly circular aperture with a very sharp edge has been cut, open to the sky. Sitting on a bench, in daylight, all attention focuses upon the intense, radiant circle of sky that contrasts with the lower light levels that it disperses in the interior like a haze. This light is the interface between internal and external space.

The light of the sky continually reveals its temporality, shifting according to the time of day, the season and the prevailing weather. Whether flecked or thick with cloud, full of stars or midday blue, a succession of intense colours dazzles the eye and conditions the glow or gloom of the interior. The bench invites visitors to sit and look at the circular aperture, and while at first they may seek to glean particular features within the sky, or to situate the experience within a conceptual framework, after a while, as we sink into the work, the intensity of the light absorbs our attention. The sky garners a focused attention in a way uncommon when outside, and acquires solidity because of the brilliance of its colour and luminosity. As dusk descends, the sky seems to become closer as the gloom of the interior blurs details within, and sunset and moonbeams tint particular sides.

We are seeing light in a pure form here, not as it refracts off the textures and features of the landscape. Isolated from the everyday surroundings with which we usually perceive it, light is revealed as integral to the experience of the world. But more than this, the depth, angles and height of the inside walls and ceiling seem to change according to the shifting qualities of light. Turrell’s work thus makes us aware of the ways in which we perceive light. We can’t be sure what we are seeing is there, or whether our eyes are being tricked. In addition, attention is drawn to the sky, which is usually sensed as a sort of neutral background above and around us. Here, it is the central focus and with its changing light and colour it seems to take on a solid, material form. This work does not only make us aware of light: far from any roads or houses, the interior also rings with the echoes of sounds made by visitors or amplifies birdsong, wind or the buzz of an aeroplane from outside, but at other times encloses an unfamiliar and complete silence.